How does the Compound Interest work?

Start with your principal amount P Then: Determine the annual rate r and how often it compounds (n times per year) Then: Apply the formula: A = P(1 + r/n)^(nt) Then: The difference A − P is the total interest earned.

Can you give an example of how to use the Compound Interest?

Example: Input $1,000 at 5% for 10 years (annual) gives a result of $1,628.89 (1000(1.05)¹⁰ — earned $628.89 interest).

Is the Compound Interest free to use?

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

How accurate is the Compound Interest?

Our Compound Interest uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

Can I use this Compound Interest for real financial decisions?

This calculator is for educational and estimation purposes. For major financial decisions — especially mortgages, investments, or tax planning — always consult a qualified financial adviser.

Finanțe

Compound Interest

Compound Interest Calculator

Principal Amount

Annual Interest Rate

Time Period

years

Compounding

Variable Key

A= future valueP= principal (initial)r= annual rate (decimal)n= periods per yeart= years

Compound interest formula

Standard formula for periodic compounding.

Interest earned

Continuous compounding

Limit as compounding frequency → ∞.

Find principal

How much to invest today to reach a goal.

Find rate

What annual rate is needed?

Rule of 72

Approximate years to double at a given rate.

A= future value

P= principal (initial)

r= annual rate (decimal)

n= periods per year

t= years

Compound interest calculates interest on both the initial principal and the previously accumulated interest. Unlike simple interest (which only grows on the principal), compound interest grows exponentially — your interest earns interest. Einstein reportedly called it "the eighth wonder of the world."

Rate	Years to double	Exact years
1%	72	69.66
2%	36	35.00
3%	24	23.45
4%	18	17.67
5%	14.4	14.21
6%	12	11.90
7%	10.3	10.24
8%	9	9.01
10%	7.2	7.27
12%	6	6.12

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Pro Tip

The frequency of compounding matters most at higher rates. At 1%, daily vs annual compounding adds almost nothing. At 10%, it adds $47 per $1,000 per year.

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Did You Know?

If you had put $1 in a bank in the year 1 AD at 5% compound interest, by the year 2000 it would be worth more than all the gold ever mined on Earth.

References

Articole înruditeEN

→

Compound Interest Explained: The Formula, Examples, and Why It Matters

8 min read

→

How to Calculate Compound Interest by Hand

6 min read

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Toate dispozitivele

Compound Interest

Compound Interest Calculator

Compound interest formula

Continuous compounding

Find principal

Find rate

Rule of 72

Ce este Compound Interest?

Cum să Compound Interest

Exemple rezolvate

Diagramă vizuală

Cazuri speciale

Rule of 72

Continuous compounding

Doubling Time by Interest Rate (Rule of 72)

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